{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2022:7QFR6XBACVYXEOXYXCJ2ZSZCWF","short_pith_number":"pith:7QFR6XBA","canonical_record":{"source":{"id":"2204.04266","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.med-ph","submitted_at":"2022-04-08T19:31:28Z","cross_cats_sorted":["physics.bio-ph"],"title_canon_sha256":"65c17d8157cb993d2036525b568a6c3771f74c8ca83f8646cb36da787af3cd73","abstract_canon_sha256":"cd952ecb44caf2b92c45189e3560317e264e245bedb938b072847487fc42a769"},"schema_version":"1.0"},"canonical_sha256":"fc0b1f5c201571723af8b893accb22b16f91024996d3de2316d5df9d58793eaa","source":{"kind":"arxiv","id":"2204.04266","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2204.04266","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"arxiv_version","alias_value":"2204.04266v1","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2204.04266","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"pith_short_12","alias_value":"7QFR6XBACVYX","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"pith_short_16","alias_value":"7QFR6XBACVYXEOXY","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"pith_short_8","alias_value":"7QFR6XBA","created_at":"2026-07-05T05:40:30Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2022:7QFR6XBACVYXEOXYXCJ2ZSZCWF","target":"record","payload":{"canonical_record":{"source":{"id":"2204.04266","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.med-ph","submitted_at":"2022-04-08T19:31:28Z","cross_cats_sorted":["physics.bio-ph"],"title_canon_sha256":"65c17d8157cb993d2036525b568a6c3771f74c8ca83f8646cb36da787af3cd73","abstract_canon_sha256":"cd952ecb44caf2b92c45189e3560317e264e245bedb938b072847487fc42a769"},"schema_version":"1.0"},"canonical_sha256":"fc0b1f5c201571723af8b893accb22b16f91024996d3de2316d5df9d58793eaa","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T05:40:30.760311Z","signature_b64":"No1M20JUu7AT90DmhfZODsw8M6sDe+JTb8lNTCO95oouVLwwkwSu7f29QPPtc5iz7OreoliYsV0gt4hPx0jQBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"fc0b1f5c201571723af8b893accb22b16f91024996d3de2316d5df9d58793eaa","last_reissued_at":"2026-07-05T05:40:30.759900Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T05:40:30.759900Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2204.04266","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T05:40:30Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"U8sdDCDG6jJSrcnfc3aSEnFJV7J45pX8oHNzrYmwuMcMiVY5Qxv135fsB6rP3nMCR3MwKpmSuOIPngz2nCT3DQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-06T03:05:14.416423Z"},"content_sha256":"456f2601b53e2aeadc8148d8ae442650c75d076e6b185c4d5f2ad59679233035","schema_version":"1.0","event_id":"sha256:456f2601b53e2aeadc8148d8ae442650c75d076e6b185c4d5f2ad59679233035"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2022:7QFR6XBACVYXEOXYXCJ2ZSZCWF","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"MP-PCA denoising for diffusion MRS data: promises and pitfalls","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":["physics.bio-ph"],"primary_cat":"physics.med-ph","authors_text":"Cristina Cudalbu, Dunja Simicic, Ileana O. Jelescu, Jessie Mosso","submitted_at":"2022-04-08T19:31:28Z","abstract_excerpt":"Diffusion-weighted (DW) magnetic resonance spectroscopy (MRS) suffers from a lower signal to noise ratio (SNR) compared to conventional MRS owing to the addition of diffusion attenuation. This technique can therefore strongly benefit from noise reduction strategies. In the present work, the Marchenko-Pastur principal component analysis (MP-PCA) denoising is tested on Monte Carlo simulations and on in vivo DW-MRS data acquired at 9.4T in the rat brain. We provide a descriptive study of the effects observed following different MP-PCA denoising strategies (denoising the entire matrix versus using"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2204.04266","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2204.04266/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T05:40:30Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"qKaniQcD6HIhEkVtwihdKdhCLqFFgMEt+t4W0+XZJhoy+2Q6/2HTTK6DXoFhiZuZLyD8W2P0g5h0fPIIIOX+AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-06T03:05:14.417176Z"},"content_sha256":"9e2ac7425fa086daed0a1068a643eb12d67668b66f5cdbbee8a25a12ada663ca","schema_version":"1.0","event_id":"sha256:9e2ac7425fa086daed0a1068a643eb12d67668b66f5cdbbee8a25a12ada663ca"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF/bundle.json","state_url":"https://pith.science/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-06T03:05:14Z","links":{"resolver":"https://pith.science/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF","bundle":"https://pith.science/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF/bundle.json","state":"https://pith.science/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF/state.json","well_known_bundle":"https://pith.science/.well-known/pith/7QFR6XBACVYXEOXYXCJ2ZSZCWF/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2022:7QFR6XBACVYXEOXYXCJ2ZSZCWF","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"cd952ecb44caf2b92c45189e3560317e264e245bedb938b072847487fc42a769","cross_cats_sorted":["physics.bio-ph"],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.med-ph","submitted_at":"2022-04-08T19:31:28Z","title_canon_sha256":"65c17d8157cb993d2036525b568a6c3771f74c8ca83f8646cb36da787af3cd73"},"schema_version":"1.0","source":{"id":"2204.04266","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2204.04266","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"arxiv_version","alias_value":"2204.04266v1","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2204.04266","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"pith_short_12","alias_value":"7QFR6XBACVYX","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"pith_short_16","alias_value":"7QFR6XBACVYXEOXY","created_at":"2026-07-05T05:40:30Z"},{"alias_kind":"pith_short_8","alias_value":"7QFR6XBA","created_at":"2026-07-05T05:40:30Z"}],"graph_snapshots":[{"event_id":"sha256:9e2ac7425fa086daed0a1068a643eb12d67668b66f5cdbbee8a25a12ada663ca","target":"graph","created_at":"2026-07-05T05:40:30Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2204.04266/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Diffusion-weighted (DW) magnetic resonance spectroscopy (MRS) suffers from a lower signal to noise ratio (SNR) compared to conventional MRS owing to the addition of diffusion attenuation. This technique can therefore strongly benefit from noise reduction strategies. In the present work, the Marchenko-Pastur principal component analysis (MP-PCA) denoising is tested on Monte Carlo simulations and on in vivo DW-MRS data acquired at 9.4T in the rat brain. We provide a descriptive study of the effects observed following different MP-PCA denoising strategies (denoising the entire matrix versus using","authors_text":"Cristina Cudalbu, Dunja Simicic, Ileana O. Jelescu, Jessie Mosso","cross_cats":["physics.bio-ph"],"headline":"","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.med-ph","submitted_at":"2022-04-08T19:31:28Z","title":"MP-PCA denoising for diffusion MRS data: promises and pitfalls"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2204.04266","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:456f2601b53e2aeadc8148d8ae442650c75d076e6b185c4d5f2ad59679233035","target":"record","created_at":"2026-07-05T05:40:30Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"cd952ecb44caf2b92c45189e3560317e264e245bedb938b072847487fc42a769","cross_cats_sorted":["physics.bio-ph"],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.med-ph","submitted_at":"2022-04-08T19:31:28Z","title_canon_sha256":"65c17d8157cb993d2036525b568a6c3771f74c8ca83f8646cb36da787af3cd73"},"schema_version":"1.0","source":{"id":"2204.04266","kind":"arxiv","version":1}},"canonical_sha256":"fc0b1f5c201571723af8b893accb22b16f91024996d3de2316d5df9d58793eaa","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"fc0b1f5c201571723af8b893accb22b16f91024996d3de2316d5df9d58793eaa","first_computed_at":"2026-07-05T05:40:30.759900Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T05:40:30.759900Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"No1M20JUu7AT90DmhfZODsw8M6sDe+JTb8lNTCO95oouVLwwkwSu7f29QPPtc5iz7OreoliYsV0gt4hPx0jQBw==","signature_status":"signed_v1","signed_at":"2026-07-05T05:40:30.760311Z","signed_message":"canonical_sha256_bytes"},"source_id":"2204.04266","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:456f2601b53e2aeadc8148d8ae442650c75d076e6b185c4d5f2ad59679233035","sha256:9e2ac7425fa086daed0a1068a643eb12d67668b66f5cdbbee8a25a12ada663ca"],"state_sha256":"54ae126a4385e310ac8231e4e8ec2798735739884d0bb3858db007b0f5bafac5"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"jcTBsrO3rkv/mzgZHu7m02+WIh3tXFpku6TqJawBLZY5rvaLr6fSxTbrS6IbteCZOmVD1RlGH2j1/3g7odTZDQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-06T03:05:14.427804Z","bundle_sha256":"03ce4e4a10214201e811bb530cb9d7634487170f836897310f851d148f87d0cb"}}